Humpback whale

The humpback whale (Megaptera novaeangliae) was a sentient aquatic cetaceous mammal species indigenous to Earth. An adult usually ranged between twelve and sixteen meters in length, and weighed approximately thirty-six metric tons. This species was well-known for its complex song, which was proven in 2286 to be a full-fledged language. This species became extinct during the 21st century due to overhunting.

The two whales seen in Star Trek IV were mechanically created by Industrial Light & Magic under project supervisor Walt Conti with help of advisor and marine mammal expert Pieter Folkens. Several scenes such as the last scene in which the two whales responded the alien probe and were swimming out into the sea were footage from a whale documentary.